Electrical switch



Sept. 24, 1940. R. HETHERINGTON ELECTRICAL SWITCH Filed Sept. 2l, 1937 2Shre ts -Lveef Sept. 24, 1940. R. HETHERINGTON 2,215,584

ELECTRICAL SWITCH Filed Sept. 21, 1937 2 Sheets-Sheet 2 Patented Sept.24, 1940 UNITED STATES PATENT OFFICE 13 Claims.

My invention relates to electric switches and supports ior they switchesby which supports the switches are made adjustable within the path ofsome moving parts by which the switches are to be operated.

A purpose of the invention is to provide a thrust switch which may beeither normally closed or normally open and which is opened or closed bythe engagement of some machine member with an operating plunger carriedby the switch.

A further purpose is to provide a multiple contact thrust switch whosecontacts may be cleaned by rotation of a switch plunger.

A further purpose is to provide a thrust switch having a plurality ofilxed contacts and a plurality of movable contacts capable of movementdirectly toward and directly away from the fixed contacts and alsocapable of revolution o1' the' contacts by rotation of the plunger forthe purpose of scouring the contacts against the iixed contacts. Thismay be either a one-way or a twoway switch.

A further purpose is to provide a spring pressed multiple contact switchwith rotational lost motion for a movable contact-carrying memberwhereby the contacts can be cleaned by revolution of the contactsthrough an angle corresponding with the lost motion.

A further purpose is to provide a spring-pressed switch plunger, capableof rotation to scour movable contacts, with limiting mechanism by whichthe extent of scouring movement is limited, desirably using the springto return the parts to approximate position and with or without lost mortion in the connection with the spring.

A further purpose is to provide a two-way switch of plunger type havingmultiple contacts and in which the contacts are capable of being cleanedby an angular movement of the plunger,

A further purpose is to provide a thrust switch with a projectingplunger and with xed contacts and movable contacts, and a resistanceautomatically inserted when the switch is partly open along withmechanism by which complete closure through the resistance andcompleteopening of the switch are controlled.

A further purpose is to control the position of a resistance-insertingswitch jointly by the action of a fabric-guiding motor and by aweb-engaging i'eeler which responds to the position of the edge of theweb.

A further purpose is to provide a band support for a contact switchacting much as a band brake,

a whereby the band may be loosened for adjustment of the position of theswitch and then tightened to maintain the switch in adjusted position.

A further purpose is to provide a plunger switch with a cylindricalorsquare exterior surface and hold it by a band similar to a brake band,of

shorter band width than the length of the cylindrical section, so thatby slacking the band the switch may be rotated or/and longitudinallymoved to positions of adjustment and the band be again tightened to holdthe switch in adjusted position.

Further purposes will appear in the speciilcation and in the claims.

My invention relates both to mechanisms and to methods which may becarried out by the use of some of the mechanisms. k

Figure 1 is a side elevation of a switch embodying my invention.

Figure 1a is a fragmentary elevation showing a variation of Figure 1.

Figure 2 is a central longitudinal section of the switch which is seenin Figure 1, the switch being closed. y

Figure 3 is a transverse section of Figure 1, taken upon line 3 3.

Figure 4 is a fragmentary longitudinal section corresponding generallyto Figure 2 but with interior parts in `elevation and with the contactsseparated.

Figure 5 is a section of Figure 2 taken upon line 5 5.

Figure 6 is an enlarged section of Figure 2 taken on line 5 6.

Figure 7 is an enlarged section corresponding in position to that online 6 6 of Figure 2 but showing a modification.

Figures 8 and 9 are fragmentary longitudinal sections correspondinggenerally to ends of the switch in Figure 2 but showing modications.

Figure 10 is an enlarged longitudinal section showing a two-way switch.

Figure 11 is a section`^of Figure 10 taken on line Il l I.

Figures 12 and 14 are fragmentary longitudinal sections showingresistance-inserting switches.

Figure 13 is an enlarged sectional elevation of the plunger of Figure12.

Figure l5 is a fragmentary sectional elevation of a portion of a clothguider showing an application to which the switches of Figures 12, 13and 15 are well suited.

Figure 16 is a fragmentary section showing a variation of the form ofthe contact carriers.

In the drawings similar numerals indicate like parts.

My switch is capable of general application. It is of plunger type andthe plunger carries the movable switch contact elements. Preferably itis the intention that the actual current passing be split vup among anumber of contact carrying elements engaged and disengaged bylongitudinal movement of the plunger.

One form of support is illustrated which will be described iirst,recognizing the fact, however, that the switch unit may be mounted inmany different ways and that the mounting shown is capable of use withswitch units of many dlierent types.

The unit 2U is mounted upon any support 2| in position for longitudinaladjustment attained by means of a holding strap or band 22 and holdingscrews or bolts 23 and 24. The strap or band grips upon much the sameprinciple as a band brake. It surrounds the switch unit.

One end 25 of the band is set to a proper position by screw 23 passingthrough the opening 26 and a screw or bolt 24 passing through theopening 21 in the other end tightens the band, putting the strap undertension and holding the tube in the longitudinal position into which itwas set before the holding mechanism was tightened.

In the illustration the switch plunger is shown as operated by an arm 28carried by a rod 29, but it is the intention that the plunger may beoperable by any conventional or special mechanism by which axial plungermovement may be given.

The reason for selection of the operating members 28 and 29 is that theswitch iinds one excellent use in operation by feelers adjacent the pathof travel, in use with cloth guiders, of which one illustration is shownin my Patent No. 2,082,- 799 for cloth guider, issued June 8, 1937.

'I'he rod 29 in the illustration, Figure 1, could be, for example, sucha feeler as that shown at 29 in Figures 1, la, 3 and 8 of above patent,though operating the switch through a bar carried by the extension offeeler arm below the n pivot point of the feeler.

If used in a cloth guider the support 2| could be any part of the frameof the guider; but equally can represent any other fixed member ofmechanism in which a switch is required.

In Figure 4 the movement of the arm 28 is shown as a swinging movementabout an axis such as the axis of rod 29 but obviously the character ofthe motion given may be greatly varied, taking its character from thetype of movement characteristic of the control member of the mechanismwith which the switch is to be used.

The unit illustrated at 20, for convenience and because it facilitatescheap manufacture is shown as a cylindrical unit; but here again theexterior and interior contours of the casing or shell are notcontrolling. It might, for example, be of square section.

With the cylindrical form shown, the center or body of the shell is.made up of a tube 30 whichis capped at 3| and 32. Both caps are open atthe ends, at 33 and 34 respectively for passage of a rotatable orangularly oscillatory plunger, it being desirable to have the plungerpass through the caps and be guided by them at both ends of the unit.This gives access for operation and for rotation of the plunger to cleanthe contacts. This oscillation capacity for contact cleaning will beseen to be true of all of the forms. The caps are held in place byscrews 35 and 39.

Each of the caps is apertured as seen in Figure 2 for the passage at 31and 38 of the conductors 39 and 40, by which the electric circuit to beclosed and to be broken is introduced within the unit.

The plunger 4|, for convenience of manufacture and insulation, is madein two parts. The end 42 and preferably most of the body of the plungeris desirably of insulating material as is also a sleeve 43 comprisingthe opposite end of the plunger. These two parts are separated in orderthat, conveniently, an electrically conducting contact carrier 44 may begripped between them. The parts are held together by screw 45. Thecarrier 44 conveniently is made in the form of a disc or annulus,preferably flat. That it need not be nat is seen in the disc or annulus44 in Figure 16.

Because it is the intention to split up the current passing through theswitch among many contacts this electrically conducting carrier 44 isstudded with electrically conducting pins 46 `which are arrangedannularly about the contact face of the carrier. The carrier iselectrically connected with conductor 39.

The carrier 44 through its conducting pins 46 makes contact with asecond, and in this case a iixed electrically conducting carrier 41,(seen in Figure 16 as 47') through electrically conducting pins 48corresponding generally with the pins 46. They are annularly arrangedabout the disc 41 and preferably have the same number and the sameradial and circumferential spacing as the pins 46.

The switch shown in Figures 1, 2 and 3 is normally closed. This normalset of the switch is effected and maintained by a spring 49 whichsurrounds the plunger and presses the movable carrier, and hence theplunger, to the right in Figure 2 through engaging the disc 44 at oneend and the interior of the cap 3| at 50 at the other end.

When the pins 46 and the movable disc are moved to the left oi Figure 2the switch will be opened and conductor 39 slacked. This openingmovement can be eiected by any means pressing against the right hand endof the plunger,

' as seen in that figure, to compress the spring 49;

and the extent of compression may vary greatly without interfering withproper operation of the switch.

It will be evident that for any predetermined movement of the operatingmeans-such as movement of the arm ZB-the extent of plunger movement isadjustable by releasing the screw or bolt 24 until the unit can beshifted longitudinally within the strap held by it and then tighteningthe screw or bolt to hold the unit in its adjusted position. At the sametime any desired circumferential adjustment of the unit may be effected.

One of many possible alternative means of adjusting the operating means(position and extent of throw) and plunger, relatively, is seen inFigure la where the arm 28', is made angularly adjustable to greatnicety by splitting the arm at 282 adjacent the shaft 29 and using thesplit ends 283 as a clamp set in adjusted position by screw 284.

One of the considerable advantages of the structure seen in Figures 2and 4 is that additiona1 slack may be given conductor 39 and, within thelimits of rotation of the disc 44, permitted by the amount of slack, theplunger can be turned from either end, irst in one direction and then inanother, while the pins of one disc are in contact with the pins of theother, the disc thus being ooscillated to rub each set of pins againstthe other, keeping the contact surfaces bright and maintaining goodcontact. The range of oscillation will be approximately twice the are ofturning permitted in one direction by the slack of conductor 35'.

Various ways are available for limiting the extent of rotation of theplunger and movable disc carried by it. By the simple expedient ofanchoring the ends of the spring against turning, the rotation in eachdirection can be limited to such winding orv unwinding of the coil ofthe spring as will conveniently take place during the turning of theplunger. This construction appears in Figures 2 and 6.

In Figure 2 the left end of the spring is shown as anchored at 5i Withinone of the caps or ends of the casing, and in Figure 6 the opposite endof the spring is shown as anchored at 52 in the movable carrier 44. InFigure 6, however, the end of the spring does not fit within an openingmerely as would be the case if it be desired to have the spring bringthe parts back to the same point at all times, but instead the springend ts into a slot 53. It may rest at any point in this slot but cannotgo beyond its limits. This permits a larger angular extent ofoscillation and provides an angular range, equivalent to the anglerepresented by the slot, Within any part of which angular range thecarrier may come to rest after the oscillation has been eiected.

In Figure 7 the carrier 442 is circumferentially recessed at 54throughout an angle corresponding to the intended angle of oscillationand oscillation is limited to this angular extent by a rib 55 whichisshown asprojecting within the interior of the casing.

In Figures 8 and 9 normally open multiple contact plunger switches areshown in fragmentary form. In each case lost motion is provided betweenthe operating mechanism, by which the plunger is moved, and the contactcarrier. It would be diflicult to adjust the operating mechanism soexactly that it would just close the switch and yet would alwaysreliably close it. For this reason provision is made for overtravel ofthe operating mechanism, provided for in the lost motion.

In Figure 8, the parts of the casing are substantially the same as thoseseen in Figure 2 except that one of the conductors 39 passes into thecasing through a lateral slot 56. 'Ihis provision better accommodatesthe movement of the electrically conducting carrier.

Upon plunger 4I is mounted an electrically conducting carrier 51provided with contacts 46 all connected with the conductor 39'. Forconvenience the annulus carrier is supported by a cup-shaped holder 58which is fastened to the plunger in any suitable way, as by pin 59. Thespring 49 forces the movable disc away from the lxed disc 41 so that theswitch is normally open. Between the spring 49 and the cup 58 is locatedan insulating cup Washer 60. The switch is intended to be closed bymovement of the plunger from right to left in this Figure 8.

At some intermediate point in the plunger a lost motion mechanism islocated. It is shown as comprising a spring 6I and a sleeve 62 slottedat 63 to pass longitudinally over one or both of pins 64.

The spring 6l requires more pressure to compress it than does the spring49', with the result that with operation of the plunger to the left inFigure 8, the operating means-not shown--will push the plunger to theleft in the figure and the plunger will move bodily to the left untilthe contacts on the two "discs engage to close the switch. Up to thistime there will be no material comprssion of spring 6I. is madeoverthrow of the movement oi the oper- However, after contact atingmechanism will result merely in compres.

slon oi the spring 6 I.

In the form shown in Figure 9 the shell 302 is provided with an interiorshoulder 65 against which an electrically conducting `carrier in theform of an annulus 51 rests in the normal open position of the switch.This annulus is carried by a cupped mount 58', but in this case themount 58' and annulus differ from the otherwise generally correspondingstructure in Figure 8 in that the cupped mount and the annulus are notcarried by the plunger in Figure 9 but are free from the plunger, asseen by the spacing therefrom at 66. They are free also to move in theshell.

Two springs are used, 61 which presses the carrier 51' to the rightagainst the annulus and the spring 68 which is internal to the cuppedmount and which is a lighter spring than is the mount spring. One end ofthe spring 68 is insulated by a washer. Instead of washer 60 at the cupend I may use a flat washer 60 at the opposite end. Y

The spring 68 rests against the mount at one end and, at the other end,presses a movable carrler in the form of disc 69 which is mountedbetween two separated parts of the plunger, as is the movable disc inFigure l, but, differing from the other figures this disc 69 is in theposition of the fixed discs of the other figures. It and the annulus 51both carry electrically conducting contacts 46 and 48, respectively asdo the contact parts in the other figures.

Because spring 68 is lighter than spring 61, it will compress to thepoint of engagement between the contacts 46 and 48 before the spring 61begins to compress.

The arrangement of the two springs is intended to take care of overthrowor overtravel of the operating mechanism which engages the righthand endof the plunger in Figure 9, as in Figure l, and pushes the plunger tothe left. When this takes place the spring 68 compresses iirst untilcontact is made. The disc 69 with its contact points then carries theannulus 51 with it for any overthrow movement with consequentcompression of the spring 61. The electrical circuit connections aregenerally as they appear in Figure 1.

In Figures 10 and 1l the two-way switch is shown making contact at bothends of the switch movement. 'I'he casing or shell is generally likethat in Figure 2 with some differences of dimension, by reason of whichthe shell is indicated as 303 and the caps as 3| and 32.`

The shell is apertured at one side at 56 and the middle conductor,adapted to be connected to either of two other conductors, as shown at10 is brought in through this aperture and for convenience also througha nipple 1I which is fastened to the contact carrying drum 12. It willbe seen that this nipple 1| acts also as a plug by which the drum 12 canbe rocked by hand to clean the contacts. Engagement of the sides of thenipple against the limits of the aperture restricts the rocking movementto any desired angle.

The conductor 10 is connected by branch conductors 13 and 14 withelectrically conducting carriers, discs 15 and 16, one at each end ofthe drum. Each of these discs carries contacts, such as 46, forengagement with corresponding contacts, such as 48, on fixedelectrically conducting carriers, discs 41, connected, respectively,with conductors and 40'.

'I'he drum 12 is a mere support for the contact 7s devices and isconnected with the plunger 4|2 so as to travel with it. This plunger maybe uniform throughout most of its length and desirablyprojects at bothends, at one end for engagement by an operating member and at the otherend for alternative engagement for the purpose of oscillation of thedrum and its contacts.

The drum is spring-pressed toward the right in Figure 10 by a spring 11so as normally to close the contacts and to hold them closed at theright-hand side of the figure. Movement of the plunger and drum to theleft breaks that engagement and subsequently, if carried far enough.closes the contacts at the left in this figure.

'I'he end of the plunger is shown as of reduced diameter at 18 so as togive room for a sleeve 19 flanged at 80. This flange forms an abutmentfor a spring 8|. The opposite end of the spring 8| engages the interior82 of a cap 83 which is kept from removal .from the flanged sleeve by athreaded collar 84.

The spring 8| is relatively stiifer than is spring 11 with the resultthat, with engagement of any suitable operating means against the cap83, the spring 11 first yields and allows movement of the drum to theleft until this movement has been stopped by closing of the circuit atthe left in the ligure. Any additional travel (overtravel) of theoperating means is taken care of by subsequent compression of spring 8|.

As will be seen the lost motion mechanism may be part of the plungerproper where it is introduced between separated plunger parts or may actseparately as in Figure 9. The drum in Figure l0 may also be consideredfor some purposes as part of the plunger.

The switches shown in Figures 12, 13 and 15 are intended for operationin connection with a motor requiring an initial operating current inexcess of the holding current. For this reason the switches completelyclose the circuit through the motor initially and subsequently breakthis short circuit connection but introduce a resistance to cut down thecurrent for holding purposes before breaking the current entirely. Anexcellent illustration of such use of a switch is found in the clothguider art where the motor is of plunger type, the moving part being thearmature of a solenoid. Because of the excellence of this illustrationsuch a solenoidal circuit is shown in Figure 14.. In this circuit themovable roll 85 of a pair of cloth guider rolls 85, 86 intended to bearupon the cloth at 81 is carried by a pair of swinging arms 88 whosepivot above the figure is not shown. These swinging arms form part of acradle having a cross bar 89 which is connected through a spring 90 witha roller carrier 9| whose roller is shown at 92.

The entire cradle can therefore be shifted and released by cam 93swinging about a shaft 94. The shaft is connected with a lever 95 in theform of a fork which is engaged by the upper end 86 of a solenoidarmature 91, the solenoid for which is shown at 98.

The solenoidal armature passes through the solenoid winding at 99 whereit is connected with the plunger |00 of one of my switches |0|, by links|02 fixed to one of the connected parts and having connection with theother through a pin |03 operating in a slot |04.

Shifting now to Figures 12 and 13 and to the switch there shown, theplunger |00 is rigidly connected with a carrier |05 having thereoncontacts 48 to engage with contacts 46 on a carrier |06. The carrier |05is shown as of the general type oi' cupped carriers shown in Figures 8and 9. The carrier |05 is downwardly pressed by spring |01 actingagainst cap |08 of casing |08'.

The plunger |00 is split into three parts, an upper insulation section|09, an intermediate resistance section ||0 and a lower insulationsection projecting through below the bottom of the casing. The parts arejoined by screw l2 on the upper section screwing into the intermediatesection and screw ||3 on the intermediate section screwing into thelower section.

'I'he resistance section 0 is electrically connected at all times withthe cupped carrier |00 and is in slidable connection at its lower endwith the stationary carrier |06 unless disconnected by far-enough upwardmovement of the plunger |00, that is unless lifted to a positionsomewhat higher than in Figure 12. The resistance section ||0 isprovided at its lower end with a ring ||4 of good electricalconductivity which makes and breaks contact with a corresponding ring I5in good electrical engagement with the carrier |06. with the purpose andintent that when the contacts of the two carriers are together thecircuit shall be closed at this point substantially without resistance,but, that with upward movement of the plunger, as the contacts of thetwo carriers are separated the resistance ||0 is interposed in thecircuit and is maintained in this circuit until the upward movement ofthe plunger has proceeded far enough to break the engagement between thetwo rings or collars.

The electrical circuit is shown as passing from a source of current ||6through the solenoid 98, thence from the solenoid by conductor ||1 tothe cupped carrier |05, from it either directly through the contacts orelse directly through the resistance ||0 to the carrier |06 and from itthrough conductor |8 back to the source of current.

The plunger as shown will be lifted finally to break the circuitaltogether, i. e., to lift the plunger to a point where the two collarsno longer engage. This lifting is effected by usually a control element,illustrated as a rocker arm ||9 rocking about shaft |20, due to themovement to the right, as seen in Figure 12, of the rocker arm |2| rigidwith the same shaft. The rocker arm |2| is itself controlled by the edgeof the traveling web 81, Figure 14.

In Figure 14 the rocker arm |2| is shown as shifted and allowed toreturn bymovement toward and away from the observer of feeler arm |22pivoted at any suitable point. In the illustration this pivot pointwould lie back of the solenoid.

Illustration of the operating mechanism is not intended to be restrictedto the construction shown but to comply with the statute that oneoperative construction be shown.

The construction in Figure 15 is intended to be eective for the samepurpose as that in Figure 12 and intended to be capable of operation bysimilar means.

The plunger |00 carries the lost motion link plates |02, as in Figure12, with slots |04 for pin |03. The shell |08 and cap |08' may besubstantially the same as in Figure12. The con. tact carriers |05' and|06 perform the same function of making or breaking contact and arepressed, |05 toward |06, by a spring |01.

One marked difference between the structure of Figure12 and that ofFigure 15 s that the resistance in Figure 12 is self-contained, i. e.,is located within the switch itself. whereas in Figure 15 the resistance||0' is indicated as located wholly outside of the switch.

The carrier |05' is a friction fit upon the plunger and in the whollyclosed positionv of the switch shown engages an electrically conductingring or sleeve ||4' which is electrically connected through resistanceH0' with the carrier |06. When upward movement of the plunger begins,carrier separates from carrier |06. The circuit is not then interruptedbut is completed through the resistance.

Upward movement of the plunger may be con` tinuous-for some uses, wherethe interval of time thus provided during which the resistance isincluded proves suicient and where all of the movement is to be eiectedby the same means; but in the cloth guider use shown the initialmovement of the plunger is effected by the solenoid and the resistanceis intended to be kept in the circuit until feeler nger actuation causesthe plunger to move the rest of the way. It therefore moves in twosteps, the first separating the carriers and the second lifting theplunger free from electrical connection with carrier |05 to open thecircuit. Stops |23 limit upward movement of the carrier |05 so that withupward plunger movement, when the carrier |05 meets the stops it becomesstationary.

When the plunger again moves, it passes through the carrier to a pointwhere the sleeve ||4' ceases to engage the electrically conductingcarrier |05 and the circuit, which intermediately has been completedwhen the outside resistance ||0 is broken.

In the lower part of the plunger |00 I show the lost motion mechanism ascomprising a spring |24 stiffer than the spring |01 and a sleeve |25fastened to one of the parts and slotted at |26 to pass over the ends ofa pin |21 in the other part. The sleeve guides and laterally supportsand the spring yields to take care of operating overtravel.

The condenser |28 is thrown across the two carriers, Figures 12 and 15,so as not only to quench the arc when the circuit is opened but to actas a capacitor also, charging and discharging when the circuit is closedand opened, increasing the power and permissible number of operationsper minute of the solenoid or other motor.

In Figure 16 carriers 44 and 41 are shown as movable and fixed carriersrespectively. The movable carrier is held between two parts of a plunger4| as in Figure 2. The contacts 46 and 48 engage properly in closedswitch position of the parts.

'Ihese carriers are regarded as effectively ldiscs and annuli just asare the carriers in Figures 2 and 8 for example, notwithstanding that inFigures 8 and 16 the supporting electrical conducting material formingthe carriers is not iiat as in usual discs and annuli.

It will be evident that with a normally closed switch a single springonly is needed. One simple construction is seen in Figure 2. Reasonableovertravel of the operating means makes no difference. Where there is anormally open switch, however, provision for overtravel of the operatingmeans is desirable if not essential. It can be provided either in theoperating mechanism itself or by lost motion in the plunger unit, thisresilient lost motion offering greater resistance to compression thandoes the spring between the carriers.

In all of the forms shown the contact carriers can be oscillated withopposite contacts in engagement to clean the contacts. This appears.very fully in the forms of Figures 2, 8, 9, v1|) and 16, but is not soobvious in Figures 12 and 15. In these two figures what have been calledslotted plates |02 are preferably in fact U-shaped yokes having thebends of the yokes at |29 swiveled by pins |30 extending into the endsof plungers |00 and |00 so that without altering the positions of theyokes carrying these plates |02 the plungers can be engaged at theirlower ends to oscillate the plungers with the contacts in closedposition cleaning the contacts 46 and 48 eiectitvely, as' in the othergures. The amount oi oscillation is, as in the other ilgures, dependentupon the play allowed in the electric wiring and subject to any meanswhich may be thought desirable for limiting angular movement.

It will be evident that the two way switch of Figures and 11 presentsthe characteristics of both of the switches of Figures 2 and 8 in thatthe switch is normally closed at one end and is normally open at theother end. The extent of throw before the normally open contacts areclosed may be made suilicient so that with short throw operation to theleft the normally closed switch at the right may be opened withoutclosing the normally open contacts at the left of Figure 10, using theswitch as a single throw switchor the second set of iixed contacts, atthe left need not be Wired up resulting in the same single throw type ofoperation. -With stroke of the operating mechanism equal to or greaterthan that necessary for closing of the switches at the left, this switchof Figure 10 becomes effective as a double throw switch.

The operation of the structure oi Figures 12 and will be described inconnection with the solenoid and the special operating mechanism shownin Figure 14 as a convenience but with the thought that the switches areof value in any location where a three position switch is needed whichgives short-circuiting contact in one position, opening of this contactwith interposition of a resistance between the contacting parts for asecond position and a wholly open circuit in the third position.

When the main switch-not shown-controlling the supply of current to theswitches in question is turned on, in this case applying current throughthe switch to the solenoid, the contacts upon the carriers are closedbecause the springs |01 and |01 have pressed the switches to full closedpositions. As a result the voltage available is connected to thesolenoid coils, lifting the solenoid armature 99 or 99 and lifting thepins |03 from some position well down in but above the bottom o! theslots |04/to a point above the previous upper end of the slots so thatthe pins |03 engage the upper ends of the slots and lift the plungers toa point such as shown in Figure 12 where the contacts no longer engage.This breaks the short-circuiting closure of the switches and, witheither switch, opens it to a point suilicient to introduce theresistance I0 or I0', but not suiiicient wholly to interrupt thecircuit.

The resistance ||0 or ||0' is made suiiicient to cut the current down tothat which is desirposition in Figure 15 and the contacts are shown inintermediate position with the resistance interposed in the circuit inFigure 12.

When the solenoid has been energized and during its holding action(Figure 14) the tilting and holding of cam 93 presses the movable rollI5 (resiliently, by reason of the spring) toward the xed roll 86 withthe cloth 81 between.

The grip of the rollers causes the cloth to be drawn toward theobserver, causing the feeler nger |22 to push lever |2| toward theobserver, lifting the plunger control element, the rocker arm H9 andthereby lifting the plunger as in Figure 12 to a point where the circuitis broken altogether.

When the circuit opens the solenoid armature drops, releasing the biteof the roll upon the travelling web 81, permitting the web 81 to retract(away from the observer in Figure 14). This in turn permits downwardmovement of the control element ||9 with corresponding downward movementof the plunger 00. It will be understood that the drop of the solenoidarmature to its low position does not itself directly affect theposition of the plunger |00 which continues to be held up by the controlelement l0 until the control element moves downward in response toinward movement of the travelling web.

As the web 81 moves inward, the plunger control element IIB movesdownward with corresponding downward movement of the plunger 00 andcarrier |05, closing the resistance connection between the contactcarrier members |05 and |06 (Figure 112) somewhat before the plunger |00and its contact carrier |05 are in their intermediate position of Figure12.

Closure of the contact causes energization of the solenoid through theresistance H0, but because of proper selection of the resistance withrespect to the characteristics of the solenoid, the energization of thesolenoid is inadequate to lift the solenoid armature until thedownwardly moving plunger brings direct engagement between the contacts48 and 46, when the increased energization of the solenoid frombypassing the resistance ||0, lifts the rsolenoid armature to repeat thecycle as already described.

There is a slight difference in operation between the structures ofFigures 12 and 15.

On the upward armature-actuated partial stroke of the solenoid themovable carrier |05 and the plunger travel together to a point where theresistance section of the plunger is interposed between the two carriersbut the circuit is not broken. When the plunger is lifted further inresponse to feeler finger actuation both the movable carrier and theplunger lift to a point where circuit is opened.

In the corresponding movement for Figure 15 the plunger and movablecarrier lift together by reason of the solenoid armature movement. Thismovement may continue not only until the movable carrier reaches thestops but until there has been partial travel movement of the plungerwithin the movable carrier, just so the contact carried by the plungerhas not electrically separated from the movable carrier. In the secondpart of the stroke, feeler actuation lifts the plunger suiiciently tobreak the electrical engagement between it and the movable carrier.

In the form of Figure 15 on the downward stroke the iirst downwardmovement of the plunger causes the plunger-supported movable carrier toelectrically engage through the contacts the flxed carrier. This takesplace before the circuit is completed. Subsequently the fixed carrieracts as a stop for movement of the movable carrier and the plungercontinues its movement through to a point where the electricallyconducting ring or sleeve upon it engages with the movable carriercompleting the circuit through the contacts 46 and 40.

It will be evident that the sleeve or collars Ill, H5, and lll' shouldbe made of good conductors of electricity such as silver or copper andthat oxidation may be prevented-for example by light chromium plating-ifthe advantage from chromium plating warrent the reduction in currentcarrying capacity in any installation.

In view of my invention and disclosure variations and modiiications tomeet individual whim or particular need will doubtless become evident toothers skilled in the art to obtain part or all of the benefits of myinvention without copying the structure shown, and I, therefore, claimall such in so far as they fall within the reasonable spirit and scopeof my invention.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is:

1. A multiple contact plunger switch comprising a longitudinally movableplunger, a pair of electrically conducting contact carriers, one fixedand the other supported by the plunger, contacts mounted upon thecarriers, a plurality upon each of the carriers adapted to interiitthose upon one carrier between those upon the other carrier and toprovide multiple parallel electrical connections between the carrierswhen the contacts of one carrier engage those of the other carrier, acasing about the carriers and plunger, connections from the carriers tothe outside of the casing and a spring about the plunger pressing themovable carrier toward its normal position and normally positioning theswitch in its normal position.

2. A multiple contact plunger switch comprising a longitudinally movableplunger, a pair of electrically conducting contact carriers, one fixedand the other supported by the plunger, contacts mounted upon thecarriers, a plurality upon each of the carriers adapted to interiitthose upon one carrier between those upon the other carrier and toprovide multiple parallel electrical connections between the carrierswhen the contacts of one carrier engage those of the other carrier, acasing about the carriers and plunger, connections from the carriers tothe outside of the casing and a spring about the plunger pressing themovable carrier toward its normal position and normally positioning theswitch in its normal position, the plunger being free to rotate, topermit scouring of the contacts, those of one carrier against those ofanother.

3. A multiple contact plunger switch comprising a longitudinally movableplunger, a pair of contact carriers, one fixed and the other supportedby the plunger, contacts mounted upon the carriers, a casing about thecarriers and plunger, connections from the carriers to the outside ofthe casing and a spring about the plunger pressing the movable carriertoward the fixed carrier and normally closing the switch, the plungerbeing rotatable and the spring being anchored at both ends in fixed androtatable parts to limit rotation and to return the plunger rotarily bythe spring.

4. A multiple contact plunger switch comprising a longitudinally movableplunger, a pair of contact carriers, one fixed and the other supportedby the plunger, contacts mounted upon the carriers, a casing about thecarriers and plunger, connections from the carriers to the outside ofthe casing and a spring about the plunger pressing the movable carriertoward the fixed carrier and normally closing the switch, the plungerbeing rotatable and the spring being anchored at both ends, with lostmotion in the anchorage at one end, limiting rotation and returning theplunger rotarily by the spring.

5. A multiple contact plunger switch comprising a longitudinally movablerotatable plunger, a pair of contact carriers, one fixed and the othersupported by the plunger, rounded contacts mounted upon the carriers, acasing about the carriers and plunger, connections from the carriers tothe outside of the casing, a spring about the plunger pressing themovable carrier toward the fixed carrier and normally closing the switchand means for limiting the rotation of the plunger.

6. A multiple contact unit, comprising a casing, a pair of contactcarriers, one fixed and the other movable and each having a plurality ofcontacts spaced and of curved contour and adapted to interfit the curvesof the contacts on one carrier between the curves of the contacts on theother, a rotatable plunger upon which the movable carrier is mounted, aspiral spring about the plunger engaging the movable carrier, normallyholding the fixed and movable contacts together and circuit connectionsfor the fixed and movable contacts, that for the movable contactsallowing revolution of the movable contacts for cleaning engagement withthe fixed contacts.

7. A multiple contact plunger switch, comprising a casing, a plungermovable longitudinally of the casing and rotatable therein, electricallyconducting contact carriers, one fixed and surrounding the plunger andthe other mounted upon the plunger transversely thereof, contact pinsarranged annularly about the two carriers and adapted to engage inclosed switch position, circuit connections for the two carriers, thatto the movable carrier permitting partial rotation of the carrier, andspring means for normally holding the switch open and a second springmeans, stiffer than the first, between the operating member and themovable contact carrier, permitting plunger movement subsequent toclosing of the contacts.

8. A multiple contact plunger switch, comprising a casing, a plungermovable longitudinally of the casing and rotatable therein, electricallyconducting contact carriers, one fixed and surrounding the plunger andthe other mounted upon the plunger transversely thereof, contact pinsarranged annularly about the two carriers and adapted to engage inclosed switch position, circuit connections for the two carriers, thatto the movable carrier permitting partial rotation of the carrier, andspring means about the plunger adapted to hold the switch normally openand a lost motion terminal upon the plunger comprising a spring aboutthe plunger, an abutment for the spring, a cap about the spring andmeans for retaining the cap.

9. A multiple contact plunger switch, comprising a casing, a plungermovable longitudinally of the casing and rotatable therein, electricallyconducting movable contact carriers, one mounted about the plunger andthe other mounted upon the plunger transversely thereof, a stop for thecarrier about the plunger, holding it away from the position of rest ofthe other carrier, contact pins arranged annularly about the twocarriers and adapted to engage in closed switch position, circuitconnections for the two carriers, one connection permitting partialrotation of one of the carriers, spring means about the plunger pressingthe carrier about the plunger against its stop and weaker spring meanspressing the two carriers apart.

10. ln a device of the character stated, a casing, fixed and movableswitch contact carriers normally spring pressed toward closure, aplunger upon which one of the carriers is mounted and with respect towhich it can move, stops limiting the movement of the movable carrier, acontact upon the plunger engaged by the movable carrier in one plungerposition and disengaged therefrom in another plunger position, aresistance connected electrically between the contact and the fixedcarrier and outside the plunger, and successive means for moving theplunger, first to disconnect the contacts so that the circuit passesthrough the resistance and then to open the circuit.

11. In a device of the character stated, fixed and movable contactcarriers, Contact elements supported by the carriers, a plunger uponwhich one of the carriers is mounted and can move, a spring pressing themovable carrier in a direction toward closure, stops engaged by themovable carrier, a Contact carried by the plunger engaged by the movablecarrier in one plunger and electrically disconnected therefrom inanother plunger position, a solenoid, a lost motion connection betweenthe solenoid and the plunger and a resistance between the contact andthe movable carrier.

l2. A multiple contact plunger switch comprising a longitudinallymovable plunger, a pair of electrically conducting contact carriers, onefixed and the other supported by the plunger, multiple contacts mountedupon each of the carriers, the contacts of one carrier being adapted tomate with those of the other carrier, a casing about the carriers andplunger, connections from the carriers to the outside of the casing, aspring about the plunger pressing the movable carrier away from thefixed carrier, normally holding the switch open and a second springstiffer than the first in the line of operation of the plunger.

13. A multiple contact plunger switch, comprising a casing, a plungermovable longitudinally of the casing and rotatable therein, electricallyconducting contact carriers, one fixed and surrounding the plunger andthe other mounted upon the plunger transversely thereof, contact pinsarranged annularly about each of the two carriers and adapted to engagethe pins on one carrier with those on the other carrier when in closedswitch position, circuit connections from the two carriers, that to themovable carrier permitting partial rotation of the carrier, and springmeans about the plunger adapted to hold the switch normally open.

ROBERT HE'I'HERINGTON.

